This is the final rangefinder produced by Zeiss Ikon, as it found itself in a precarious position as the 1970s opened.
While most people call this the Contessa S 312, in fact, it really is the Zeiss Ikon S 312, making it the second camera to be brought to market with the Zeiss Ikon name, rather than a model name, such as Contarex, Contessa, Ikonta, etc. The other is the SLR Zeiss Ikon SL 706.
Sharing much with the Contessa S 310, the little S 312 packs a lot into the same small body. It features aperture-priority autoexposure with a shutter-speed range of four seconds to 1/500.
There was just one lens available: a coated f/2.8 Tessar.
It's a small camera, slightly larger than a Rollei 35. Among its features: Rangefinder focusing with a close-focus distance of 0.9 meters; ASA/DIN range from 25/17-400/27; hot shoe for flash synchronization and a sync post for off-camera flash, automatic resetting frame counter, an on-off switch for the meter; aperture range of 2.8 to 22; film load-indicator, removable back, single-stroke film advance, battery test button that casts light over the frame counter, threaded port for a cable release and a built-in lens hood.
The viewfinder corrects for horizontal parallax but not vertically. There are two small marks on either side of the aperture scale that can be used for vertical parallax adjustment.